Community antenna television (“CATV”) systems provide a premise with many services including, but not limited to, Internet service, telephone service (e.g., voice-over-Internet protocol (“VOIP”) telephone), television service, and music service. Each of these services requires the CATV system and the premise to exchange bandwidth, such as, for example, radio frequency (“RF”) signals, and digital signals, among many others. Typically the CATV system is configured to use bandwidths that are separated from one another for the purpose of grouping transmissions, and more often the grouping is by the direction that the transmission are transmitted or received in the CATV system. That is, transmissions that have one frequency may be transmitted or received relative to the premise and/or the head-end of the CATV system in a direction that is different from transmissions that have a second frequency. As one example, transmissions that originate from the head-end facility and are transmitted to the premise are referred to herein as a downstream bandwidth, while transmissions that originate from the premise and are transmitted to the head-end facility are referred to herein as an upstream bandwidth.
FIG. 1 illustrates one example of a CATV system 100 that includes a head-end facility 102 and a plurality of local networks 104, which are connected to the head-end facility 102 by distribution lines 106. Each local network 104 includes a feed tap 108, a drop-line 110, and a portion 112 with a premise 114. The premise 114 is connected to the head-end facility 102 via the combination of the distribution line 106, the feed tap 108, and the drop-line 110. The system 100 further includes a downstream bandwidth 116 and an upstream bandwidth 118, both of which are discussed in more detail below.
Typically the downstream bandwidth 116 and the upstream bandwidth 118 are defined by upper and lower cutoff frequencies. Exemplary frequencies for the downstream bandwidth 116 are more than about 54 Mhz, and in one particular example the frequency can be from about 54 Mhz to about 1002 Mhz. Frequencies for use as the upstream bandwidth 118 can be greater than about 40 Mhz such as 88 Mhz, less than about 40 Mhz, and in one example the frequency is from about 5 Mhz to about 40 Mhz.
The terms “downstream bandwidth,” and “upstream bandwidth” are used herein to generally describe some of the transmissions that are transmitted, exchanged, and manipulated within systems such as the CATV system 100. As is inherent in systems such as system 102, these terms are used in a manner that describes any number of transmissions. Moreover, each of the transmissions that are described by these terms may exhibit properties that are similar to, or different from, other the properties of other transmissions. These other transmissions can also be classified by the terms “downstream bandwidth,” and/or “upstream bandwidth” as used in connection with the various embodiments of the present invention that are disclosed, described, and contemplated herein.
In addition to CATV systems, systems that are configured similar to the system 100 of FIG. 1 include, but are not limited to, other uni-directional, and bi-directional communication systems that communicate with remote premises. Similar systems may transmit the transmissions via transmission lines, e.g., distribution lines 106, and drop lines 110. Transmission lines of the type used as the transmission lines are typically transmission-carrying conductors such as, for example, coaxial cable, shielded cable, multi-core cable, ribbon cable, and twisted-pair cable, among others.
Premises that are connected to the system 100 such as the premise 114 include, for example, homes, apartments (e.g., individual apartments, and/or townhomes), and businesses. These premises can have any number of devices and or appliances (collectively, “premise devices”) that are coupled either directly or indirectly to the drop-line 110. Techniques and equipment that are used to connect each of the individual premise devices to the head-end facility 102 are generally well-known to those familiar with CATV systems, and therefore a detailed discussion is not provided for purposes of the present discussion.
The premise devices can include, but are not limited to, modems, desktop computers, notebook computers, televisions, gaming consoles, set-top-boxes (STB), and set-top-units (STU), among many others. These are generally configured to communicate with the head-end facility 102, via the downstream bandwidth 116 and the upstream bandwidth 118. For example, the premise devices typically receive the downstream bandwidth 116 from the head-end facility 102, and can transmit the upstream bandwidth 118 to the head-end facility 102.
Improvements in communication between the premise devices and the head-end facility 102 can include the addition of devices for conditioning the upstream bandwidth. These devices can modify the RF level of RF traffic in the upstream bandwidth such as by inserting a gain and/or an optimized amount of attenuation. The amount of attenuation can reduce the RF level of the RF traffic in a way that optimizes the exchange of data and information between the premise and the head-end facility.
It is noted, however, that in systems like the system 100, transient events such as power outages can affect multiple local networks 104 and an even larger number of premises 114. When the premises 114 include conditioning devices such as those discussed immediately above, the loss of power can potentially overload the head-end facility 102 with simultaneous RF level re-adjustments. That is, the optimized attenuated RF levels that are established by the conditioning devices could, upon power failure, revert to higher, un-attenuated RF levels. This is so because the conditioning devices are often equipped with volatile components that do not operate without power.
Though power outages can affect the conditioning devices, it is likely that the devices of the network 104, e.g., those devices located at the head-end facility 102, are equipped to continue normal operation. The provider can, for example, have large battery back-ups, generators, and other alternative means available to provide power to the critical devices and components that are used to communicate with the premises 114. Likewise, premise devices such as modems may be equipped with alternative power supplies that permit the devices to continue to exchange, in whole or in part, data traffic with the head-end facility 102. In one example, owners can provide an uninterruptible power supply (“UPS”) that can bridge the power gap until power is restored to the premise 114.
Since the exchange of RF traffic may not be altogether eliminated, the likelihood exists that some of the premise devices can continue to transmit data at un-attentuated RF levels. Although this un-attenuated data traffic may be generally acceptable when it occurs from a limited number of premises, it becomes substantially more problematic when multiple devices simultaneously begin to broadcast data traffic at these high un-attenuated RF levels. For example, the popularity of VOIP telephone services could lead to data traffic in the form of multiple, emergency calls that occur substantially simultaneously at or around the time of the power outage. These calls are often transmitted by modems, which can communicate with a cable modem termination system (“CMTS”) located at the head-end facility 102. During normal operation, the CMTS can manage the call volume, and more particularly, the call volume and other communication packets that require the attention of the CMTS. But in the event of a power outage that can lead to a surge in data traffic (e.g., a spike in VOIP call volume), the CMTS can become overwhelmed because it must simultaneously instruct each of the modems to reduce its RF level at the same time. This requirement can lead to the disruption of service, which is not acceptable for premises that rely exclusively on VOIP telephone services for their primary telephone service.
One solution to this problem is to provide in the conditioning device an alternative power supply such as a back-up battery supply. This solution, however, can inevitably add additional costs due to the complexity of the design, components, and manufacture of the modified signal conditioning devices. Moreover, while possibly solving the problem in applications that include low numbers of individual premises, the conditioning devices that include back-up devices could not be implemented over large-scale networks if only because of the maintenance time, costs, and personnel required to monitor and/or maintain the batteries in the back-up battery supplies over many hundreds, or thousands of premises.
Therefore, there is a need for a conditioning device that can adjust the RF level of RF traffic but that does not require the addition or modification of the hardware of the device. There is likewise a need for conditioning devices that provide this adjustment independently of the availability of the power supplied to the device, but that are applicable to large scale systems (e.g., CATV systems) without adding complexity to the device, requiring maintenance, or otherwise incurring additional costs.